All blur is broken - multicore rendering crashes the game - didn't before

Okay, so I have no clue what happened, but for some bizarre reason Gmod is acting like a total ass. With multicore rendering on it crashes every minute or so, though it didn’t before - and no blur turns up. Simple DoF, super DoF, motion blur - you name it.
It’s even grayed out in the options menu along with other opinions.

I run Win 7 64-bit w/AMD Phenom™ II X4 955 Processor (4 CPUs), ~3.2GHz & NVIDIA GeForce GTX 460. I have Dx11 installed, and I can (and have no problem with) games such as Battlefield 3 maxed out. I have the newest drivers for my graphics card and such.
Where is my issue lying? Any ideas folks?

“Hardware DirectX level: DirectX v8.0”

uh

I can’t change thay either for some reason - I’m not 100% sure but I think I could before. It IS a dropdown menu after all, and I have DirectX 11 fully functioning after all.

I think you need to force it to 11 in the properties in steam, but feels like it could backfire badly.

Source (the engine GMod uses) can only support up to DirectX 9.

Try right-clicking your Garry’s Mod shortcut and adding “-dxlevel 98” (no quotes). If you’re launching it through Steam, right-click on “Garry’s Mod”, and then selecting Properties -> General -> Set Launch Options and enter it there.

Thanks a ton buddy, this fixed everything!